The nanny accused of beheading a four-year-old girl and waving her severed head outside a Moscow Metro station said it was revenge for “Putin's airstrikes in Syria” while it has emerged the woman was a mental hospital patient in her native Uzbekistan.

“While people commit such crimes at the time of a sharp aggravation of the disease, they explain their actions when already in remission. One can hear some of the most incredible and fantastic versions of the motives. Some consider themselves to be Napoleons, others think they are an Indira Gandhi, etc – you name it. If there's anyone who should take [Gulchekhra Bobokulova's] words seriously, it's the psychiatrists,” Vladimir Markin, spokesman for the Investigative Committee, said on Thursday.

A Samarkand regional mental hospital in Uzbekistan confirmed on Wednesday that Bobokulova had been registered with a local psychiatrist. "Gulchekhra Bobokulova has been registered with our institution with a diagnosis of 'acute schizophrenic disorder' since 2003,” hospital officials told RIA Novosti, adding that the patient had regularly demonstrated "deviations in psyche, along with the loss of control over her actions."

In video footage leaked online on Wednesday, Bobokulova is heard speaking erratically: "I took revenge against those who spilled blood... Putin spilled blood, planes carried out bombings. Why are Muslims being killed? They also want to live," she told an investigator in the video.

She says that she had wanted to relocate to Syria, but lacked the money to move. When asked whether she wanted to join Islamic State (IS, formerly ISIS/ISIL), Bobokulova replies “I don't know,” adding that she “just wanted to live there.” She says she has been avidly reading the Koran, and that God told her that “the end of the world is coming in a second.”

Numerous videos released online on Monday recorded Bobokulova's indistinct speech as she waved the girl's severed head outside the Metro station. It was possible to make out some of her words, however, including “I hate democracy. I’m a terrorist. I'm your suicide bomber… I'm going to die in a second…The end of the world…”

A spokesman for Russia's Investigative Committee has urged media outlets not to jump to hasty conclusions regarding Bobokulova's motives, saying that she will first be given a thorough psychological and psychiatric examination.

Bobokulova appeared in court on Wednesday over the alleged murder of the girl in her care. She briefly stated that she was born in 1977 and has three sons, aged from 16 to 20. When asked if she pleaded guilty, Bobokulova replied “Yes.” She was seen smiling inside the court cage.

She was detained on Monday near Oktyabrskoye Polye Metro station in northwest Moscow, where she was filmed waving the child’s severed head and shouting “Allahu Akbar, I am a terrorist, I am a suicide bomber.”

The decapitated body of the four-year-old girl was found by a team of firefighters who were responding to a blaze in a Moscow apartment. According to investigators, the nanny waited until the parents had left the apartment with their elder child, then killed the younger girl and set the apartment on fire.

Bobokulova, who did not have a work permit, was reportedly employed as a nanny to the deceased girl for at least 18 months. She will officially be charged on March 4, and will be preliminarily detained until April 29.

Investigators are trying to identify Bobokulova’s boyfriend, who she mentioned during questioning. Her friend, Aziza Gazoeva, told RIA Novosti that Bobokulova had acted aggressively during her last visit to Uzbekistan, allegedly under the influence of her boyfriend.